The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 28, 2012
Filed:
Feb. 22, 2011
Hiroki Kimura, Chitose, JP;
Naoki Onishi, Chitose, JP;
Shoichi Tsuchiya, Chitose, JP;
Nihon Dempa Kogyo Co., Ltd, Tokyo, JP;
Abstract
Provided is a PLL circuit improving reliability while suppressing power consumption without degrading noise characteristics. The PLL circuit includes a PLL IC that divides an output frequency Fout from a VCO, compares phase with a reference signal, and feeds back a phase difference as a control voltage to the VCO. A control circuit is capable of finely setting both of a reference frequency Fref and an output frequency Fdds in a DDS circuit, and the DDS circuit generates folding signals of Fdds for Fref and an integral multiple frequency thereof based on the combination of the frequencies. A first AMP amplifies a signal, a variable filter selects a desired Fdds (desired) and a second AMP amplifies the signal and supplies the same to the PLL IC as a reference signal. The control circuit further supplies a division ratio N to the PLL IC.